__________________________________________________________________________________________ 

 

_____________________________________ 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Dichlorvos. It is one in a series of Public Health 

Statements about hazardous substances and their 

health effects. A shorter version, the ToxFAQsTM is 

also available. This information is important 

because this substance may harm you. The effects 

of exposure to any hazardous substance depend on 

the dose, the duration, how you are exposed, 

personal traits and habits, and whether other 

chemicals are present. For more information, call 

the ATSDR Information Center at 1-888-422-8737. 

This public health statement tells you about 

dichlorvos and the effects of exposure. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites make up the National 

Priorities List (NPL) and are the sites targeted for 

long-term federal cleanup. Dichlorvos has been 

found in at least 3 of the 1,430 current or former 

NPL sites. However, it's unknown how many NPL 

sites have been evaluated for this substance. As 

more sites are evaluated, the sites with dichlorvos 

may increase. This is important because exposure 

to this substance may harm you and because these 

sites may be sources of exposure. 

When a substance is released from a large area, 

such as an industrial plant, or from a container, such 

as a drum or bottle, it enters the environment. This 

release does not always lead to exposure. You are 

exposed to a substance only when you come in 

contact with it. You may be exposed by breathing, 

eating, or drinking the substance or by skin contact. 

If you are exposed to dichlorvos, many factors 

determine whether you'll be harmed. These factors 

include the dose (how much), the duration (how 

long), and how you come in contact with it. You 

must also consider the other chemicals you're 

exposed to and your age, sex, diet, family traits, 

lifestyle, and state of health. 

1.1 WHAT IS DICHLORVOS? 

Dichlorvos is a synthetic organic chemical used as 

an insecticide. Dichlorvos does not occur naturally 

in the environment, but is manufactured by 

industry. Dichlorvos is sold under many trade 

names including Vapona®, Atgard®, Nuvan®, and 

Task®. Dichlorvos may also be called DDVP, 

which is an abbreviation for its full chemical name. 

Pure dichlorvos is a dense colorless liquid that 

evaporates easily into the air and dissolves slightly 

in water. Dichlorvos has a sweetish smell and 

readily reacts with water. The dichlorvos used in 

pest control is diluted with other liquids and used as 

a spray. It can also be incorporated into plastic that 

slowly releases the chemical. The dichlorvos 

present at hazardous waste sites will most likely be 

in a liquid solution or as solid plastic pellets or 

strips. 

Dichlorvos is manufactured by a reaction between 

two other chemicals called chloral and trimethyl 

phosphite. It is also manufactured by heating a 

chemical called trichlorfon. In 1984, about 1 

million pounds of dichlorvos was manufactured in 

the United States. The main uses of dichlorvos are 

for insect control in food storage areas, 

greenhouses, and barns, and for parasite control in 

livestock. Dichlorvos is generally not used on 

outdoor crops. It is sometimes used for insect 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

__________________________________________________________________________________________ 

 

 

 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

control in workplaces and the home. Veterinarians 

also use it to control parasites in pets. 

1.2 WHAT HAPPENS TO DICHLORVOS 

WHEN IT ENTERS THE 

ENVIRONMENT? 

Dichlorvos enters the air, water, and soil during its 

manufacture and use. Wastes containing dichlorvos 

that are generated during its manufacture and use 

are sometimes disposed of in landfills. It can enter 

the environment from these landfills. Dichlorvos 

also enters the environment from accidental spills 

during transport and leaks from storage containers. 

Dichlorvos evaporates easily into the air, which is 

why it is usually used in enclosed areas. Once in 

the air, it can react with water vapor and be broken 

down. The higher the temperature and the 

humidity, the more rapidly dichlorvos is broken 

down. Experiments in greenhouses and food 

storage areas show that 90% of the applied 

dichlorvos disappeared in 3–6 hours. The products 

of this breakdown are two chemicals called 

dimethyl phosphate and dichloroacetaldehyde. 

These chemicals are less harmful than dichlorvos 

and are not believed to cause health effects in 

people. 

If dichlorvos is spilled into a lake or river, it will 

dissolve in the water. Some dichlorvos will then 

evaporate into the air, but most of it will be broken 

down when it reacts with the water. The less acid 

the water is, the more rapidly dichlorvos is broken 

down. Bacteria and other microorganisms 

(microscopic plants and animals) in lakes and rivers 

can also break down dichlorvos. In an experiment 

where dichlorvos was applied to a pond, 50% of the 

chemical was broken down in 24–36 hours. 

Dichlorvos does not seem to bind to soil. This 

means it can move through soil fairly rapidly. The 

breakdown in soil is less rapid than in air or water. 

Dichlorvos breakdown is most rapid in moist soils 

with low acidity. In a laboratory experiment with 

soil that contained 200 parts of dichlorvos per 

million parts of soil (200 ppm), 37% of the 

dichlorvos remained in the soil after 3 days. 

Dichlorvos remains for longer periods in dry, acidic 

soil. Certain bacteria and other microorganisms in 

the soil can also break down dichlorvos. 

Dichlorvos is not stored, accumulated, or 

concentrated by plants, fish, animals, or people. 

1.3 HOW MIGHT I BE EXPOSED TO 

DICHLORVOS? 

The general population is not likely to be exposed 

to dichlorvos. It has not been found in drinking 

water in the United States and only very rarely in 

outdoor air. Dichlorvos has occasionally been 

found on raw foods (fruits, vegetables, grains), but 

washing and processing destroys the residue. 

Maximum limits (ranging from 0.02 to 2 ppm) have 

been established by the U.S. EPA. Dichlorvos has 

not been found in prepared foods. 

People living near hazardous waste sites containing 

dichlorvos or near its manufacturing, processing, or 

storage facilities, could potentially be exposed. 

Because of the chemical properties, the most likely 

way a person would be exposed is by breathing in 

air contaminated with dichlorvos. Another possible 

route of exposure is skin contact with soil 

contaminated with dichlorvos. 

You are most likely to be exposed to dichlorvos if 

you are involved in manufacturing or using it. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

__________________________________________________________________________________________ 

 

 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

Chemical plant workers, transport workers, and 

pesticide applicators are the major occupational 

groups that might be exposed. People in these 

groups are mainly exposed by breathing air 

containing dichlorvos, but significant exposure 

through the skin can occur as well. An estimated 

24,000 workers in the United States are exposed to 

dichlorvos because of their occupations. Measured 

air levels in factories and workplaces have ranged 

from 0.005 to 0.08 ppm dichlorvos. 

You might also be exposed to dichlorvos in the 

home after pesticide application. You are most 

likely to be exposed by breathing air containing 

dichlorvos, but skin contact with contaminated 

surfaces, or eating food that has been left out during 

dichlorvos application can also result in exposure. 

Measured levels of dichlorvos in room air 

immediately after pesticide applications have 

ranged from 0.08 to 2.7 ppm. It has been 

recommended that people should not reenter a room 

or house treated with dichlorvos until after a 10­

hour ventilation period. 

1.4 HOW CAN DICHLORVOS ENTER AND 

LEAVE MY BODY? 

Dichlorvos can enter your body through your lungs 

if it is in the air you breathe. It can also enter your 

body through your stomach if it is in your drinking 

water or food. It can also enter through your skin. 

Dichlorvos is taken into your body very rapidly by 

any of these routes (lungs, stomach, or skin). How 

much dichlorvos enters your body depends on how 

long you are exposed and the amount to which you 

are exposed. 

Once dichlorvos enters your body, it goes into your 

bloodstream and is carried to all the organs in your 

body. There are enzymes in your liver and blood 

that rapidly break it down. These breakdown 

products are less harmful than dichlorvos. Most of 

these breakdown products quickly leave the body in 

the urine. Some of these products are broken down 

further and leave your body in your breath. 

Dichlorvos and its breakdown products are not 

stored in your body. 

1.5 HOW CAN DICHLORVOS AFFECT MY 

HEALTH? 

Dichlorvos is a member of a group of chemicals 

called organophosphorus compounds. Some of 

these chemicals are extremely harmful to insects 

and are widely used as insecticides. At higher doses 

than those used to kill insects, these chemicals can 

also be harmful to people. Dichlorvos can 

chemically react with an important enzyme in your 

brain and nerves called acetylcholinesterase and 

stop them from working properly. When this 

happens, signals sent between your nerve cells and 

to your muscles are disrupted. To understand the 

harmful effects of dichlorvos that might occur at 

levels of exposure that people are likely to 

experience, scientific studies have been done with 

people and laboratory animals. To protect the 

public from the harmful effects of toxic chemicals 

and to find ways to treat people who have been 

harmed, scientists use many tests. 

One way to see if a chemical will hurt people is to 

learn how the chemical is absorbed, used, and 

released by the body; for some chemicals, animal 

testing may be necessary. Animal testing may also 

be used to identify health effects such as cancer or 

birth defects. Without laboratory animals, scientists 

would lose a basic method to get information 

needed to make wise decisions to protect public 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

__________________________________________________________________________________________ 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

health. Scientists have the responsibility to treat 

research animals with care and compassion. Laws 

today protect the welfare of research animals, and 

scientists must comply with strict animal care 

guidelines. 

We do not know how much dichlorvos is necessary 

to cause harmful effects in people. This is because 

few people have been exposed to enough dichlorvos 

to cause symptoms of poisoning. From the results 

of animal testing, we can estimate that if a person 

breathed in air containing more than 1 ppm 

dichlorvos for more than one hour, harmful effects 

might result. Accidentally drinking as little as 1 

ounce or 30 milliliters (mL) of a pesticide 

containing 5% dichlorvos could also cause harmful 

effects. Spilling an ounce of the same strength 

dichlorvos solution on your skin and failing to wash 

it off promptly could also be harmful. 

If you have been poisoned by dichlorvos, you will 

suddenly feel nauseated, anxious, and restless. You 

may also have teary eyes and heavy sweating. If 

this happens, you should seek medical attention 

immediately. Emergency rooms have drugs that 

stop the harmful effects of dichlorvos. Further 

symptoms can include loss of bladder control, 

muscle tremors, and labored breathing. Severe 

poisoning (5 ounces or more of a 5% dichlorvos 

solution) can result in coma, inability to breathe, 

and death. 

Most people who have survived poisoning by 

dichlorvos make a complete recovery, although this 

can sometimes take several months. Dichlorvos 

poisoning does not appear to cause permanent 

damage to the nerves (a condition called "delayed 

neuropathy"). 

A few studies have been done on people who have 

been exposed to dichlorvos in the air in their 

workplaces. When dichlorvos is used properly, air 

levels of 0.01–0.03 ppm are achieved. This level 

kills most insects within one hour. In tests done 

with volunteers, exposure at about 20 times this 

level (0.23 ppm) for 2 hours a day for 4 days had no 

harmful effects. In a study in rats exposed to air 

with very high levels of dichlorvos (up to 34 ppm), 

all the animals died within 3 days. The rats showed 

similar signs of effects on the nervous system as in 

people that have been poisoned with dichlorvos. In 

general, harmful effects have not been seen in 

animals exposed to air levels of dichlorvos below 

0.5 ppm. In a 2-year study in rats, breathing air 

every day with low-to-moderately high levels 

(0.006–0.6 ppm) of dichlorvos had no effect on how 

long the rats lived or on their general health. 

In at least one case, a person who drank a pesticide 

containing dichlorvos died. The doctors who 

treated this patient were unable to tell exactly how 

much dichlorvos she had taken. Volunteers who ate 

0.03 milligrams dichlorvos per kilogram body 

weight (0.03 mg/kg) for 21 days showed no harmful 

effects. In studies where animals (rats and mice) 

have been force-fed dichlorvos, about half the 

animals died when given approximately 100 mg/kg. 

Before the animals died, they showed signs of 

harmful effects to their nervous systems similar to 

those seen in human poisoning cases. 

Two pesticide workers died after spilling 

concentrated dichlorvos on their skin and failing to 

wash it off promptly. It is not known exactly how 

much dichlorvos they absorbed through their skin. 

Experiments in animals show that dichlorvos can be 

just as harmful when it is applied to the skin as 

when it is breathed in or swallowed. Monkeys that 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

__________________________________________________________________________________________ 

 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

had dichlorvos put on their skin (50 mg each day) 

died after 10 doses. 

It is not known if exposure to dichlorvos can affect 

fertility or development of the fetus in people. 

Experiments done in animals that were fed or 

breathed in dichlorvos did not show any effect on 

fertility or health of the offspring. 

There is no evidence that exposure to dichlorvos 

increases the risk of cancer in people. Rats that 

breathed in air containing dichlorvos for 2 years had 

the same rate of cancer as rats that did not breathe 

in dichlorvos. However, a 2-year study in rats and 

mice force-fed dichlorvos showed an increase in 

certain forms of cancer. Rats had increased rates of 

cancer in the pancreas and also had more cases of 

leukemia than rats that had not been treated with 

dichlorvos. Female mice had a higher rate of a 

form of stomach cancer. 

The U.S. Department of Health and Human 

Services (DHHS) has determined that dichlorvos 

may reasonably be anticipated to be a carcinogen (a 

substance that can cause cancer). The International 

Agency for Research on Cancer (IARC) has 

determined that dichlorvos is possibly carcinogenic 

to humans. The U.S. EPA has determined that 

dichlorvos is a probable human carcinogen. 

The U.S. EPA has calculated that a lifetime of 

drinking water containing 0.1 micrograms of 

dichlorvos per liter (μg/L) would cause one extra 

case of cancer in every million people exposed to 

this level. Dichlorvos has not been found in 

drinking water in the United States. 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO DICHLORVOS? 

Two blood tests exist that can determine whether 

you have been exposed to significant levels of 

dichlorvos. These tests can be performed by any 

hospital or clinical laboratory. These tests measure 

the activity of two enzymes (called serum 

cholinesterase and erythrocyte [red blood cell] 

acetylcholinesterase) that are affected by 

dichlorvos. Dichlorvos affects these enzymes at 

lower levels of exposure than necessary to produce 

harmful effects. This means that if these enzymes 

have been affected, you will not necessarily have 

effects on your health. Many other insecticides also 

affect these enzymes. To determine whether you 

have been specifically exposed to dichlorvos, a 

laboratory test must measure the breakdown 

products in your urine. Tests of this type are not 

routinely done in hospital laboratories and your 

doctor will have to send a sample to a specialized 

laboratory. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The federal government develops regulations and 

recommendations to protect public health. 

Regulations can be enforced by law. Federal 

agencies that develop regulations for toxic 

substances include the EPA, the Occupational 

Safety and Health Administration (OSHA), and the 

Food and Drug Administration (FDA). 

Recommendations provide valuable guidelines to 

protect public health but cannot be enforced by law. 

Federal organizations that develop 

recommendations for toxic substances include the 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

__________________________________________________________________________________________ 

 

PUBLIC HEALTH STATEMENT 

DICHLORVOS 

CAS#: 62-73-7 

Division of Toxicology September 1997 

Agency for Toxic Substances and Disease Registry 

(ATSDR) and the National Institute for 

Occupational Safety and Health (NIOSH). 

Regulations and recommendations can be expressed 

in not-to-exceed levels in air, water, soil, or food 

that are usually based on levels that affect animals, 

then they are adjusted to help protect people. 

Sometimes these not-to-exceed levels differ among 

federal organizations because of different exposure 

times (an 8-hour workday or a 24-hour day), the use 

of different animal studies, or other factors. 

Recommendations and regulations are also 

periodically updated as more information becomes 

available. For the most current information, check 

with the federal agency or organization that 

provides it. Some regulations and 

recommendations for dichlorvos include the 

following: 

The U.S. OSHA has set a permissible exposure 

limit (PEL) of 1 mg/m3 (0.11 ppm) of dichlorvos for 

workplace air over a 10-hour workday. 

The U.S. EPA requires reporting of any discharge 

of dichlorvos to the environment that exceeds 10 

pounds. The EPA has also designated dichlorvos as 

a hazardous substance and specific regulations 

regarding its disposal are in effect. 

The U.S. EPA has established maximum 

permissible levels of dichlorvos in various food 

products ranging from 0.02 to 2 parts per million 

(ppm). Samples from the food supply are regularly 

tested for dichlorvos. 

1.8 WHERE CAN I GET MORE 

INFORMATION? 

If you have any more questions or concerns, 

please contact your community or state health or 

environmental quality department or: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology 

1600 Clifton Road NE, Mailstop F-32 

Atlanta, GA 30333 

Information line and technical assistance: 

Phone: 888-422-8737 

FAX: (770)-488-4178 

ATSDR can also tell you the location of 

occupational and environmental health clinics. 

These clinics specialize in recognizing, evaluating, 

and treating illnesses resulting from exposure to 

hazardous substances. 

To order toxicological profiles, contact: 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

Phone: 800-553-6847 or 703-605-6000 

Reference 

Agency for Toxic Substances and Disease Registry 

(ATSDR). 1997. Toxicological profile for 

dichlorvos. Atlanta, GA: U.S. Department of Health 

and Human Services, Public Health Service. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov